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feet broad, or thereabouts. The materials 

 whereof this mole consists, are wood and clay. 

 The beavers cut with surprising ease, large 

 pieces of wood, some as thick as a man's arm 

 or thigh, and about four, five, or six feet in 

 length, or sometimes more, according as the 

 slope ascends. They drive one end of these 

 stakes into the ground, at a small distance one 

 from the other, intermingling with them a few 

 that are smaller and more pliant. As the water, 

 however, would find a passage through the in- 

 tervals or spaces between them, and leave the 

 reservoir dry, they have recourse to a clay, 

 which they know where to find, and with which 

 they stop up all the cavities, both within and 

 without, so that the water is duly confined. 

 They continue to raise the dyke in proportion 

 to the elevation of the water, and the plenty 

 which they have of it. They are conscious 

 likewise that the conveyance of their materials 

 by land, would not be so easily accomplished 

 as by water ; and, therefore, they take the ad- 

 vantage of its increase, and swim with their 

 mortar on their tails, and their stakes between 

 their teeth, to the places where there is the 

 most occasion for them. If their works are, 



